- A smooth horizontal surface.
- A smooth inclined surface.
- A rough horizontal surface.
- A rough inclined surface.
Explanation:
A sphere cannot roll on a smooth inclined surface and on a smooth horizontal surface because there is no backward force (force of friction) to prevent its slipping.

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When a slab of dielectric material is introduced between the parallel plates of a capacitor which remains connected to a battery, then charge on plates relative to earlier charge
|
(a) Is less |
|
(b) Is same |
|
(c) Is more |
|
(d) May be less or more depending on the nature of the material introduced |

The intensity of the electric field required to keep a water drop of radius
just suspended in air when charged with one electron is approximately (g = 10 newton/kg e = 1.6 ![]()
|
(a) 260 volt/cm |
(b) 260 newton/coulomb |
|
(c) 130 volt/cm |
(d) 130 newton/coulomb |
64 small drops of mercury, each of radius r and charge q coalesce to form a big drop. The ratio of the surface density of charge of each small drop with that of the big drop is
|
(a) 1 : 64 |
(b) 64 : 1 |
(c) 4 : 1 |
(d) 1 : 4 |
In Bohr's model, the atomic radius of the first orbit is
, then the radius of the third orbit is
|
(a) |
(b) |
(c) |
(d) |
A moving coil galvanometer of resistance 100 is used as an ammeter using a resistance 0.1 The maximum deflection current in the galvanometer is 100A. Find the minimum current in the circuit so that the ammeter shows maximum deflection
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(a) 100.1 mA |
(b) 1000.1 mA |
(c) 10.01 mA |
(d) 1.01 mA |